<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <div id="todo-list-example">
        <form v-on:submit.prevent="addNewTodo">
            <label for="new-todo">Add a todo</label>
            <input
            v-model="newTodoText"
            id="new-todo"
            placeholder="E.g. Feed the cat"
            >
            <button>Add</button>
        </form>
        <ul>
            <!-- 注意这里的 is="todo-item" attribute。这种做法在使用 DOM 模板时是十分必要的,这样做实现的效果与 <todo-item> 相同 -->
            <li
            is="todo-item"
            v-for="(todo, index) in todos"
            v-bind:key="todo.id"
            v-bind:title="todo.title"
            v-on:remove="todos.splice(index, 1)"
            ></li>
        </ul>
    </div>
</body>
<script src="https://cdn.jsdelivr.net/npm/vue@2.6.14/dist/vue.js"></script>
<script>
    Vue.component('todo-item', {
        template: '\
            <li>\
            {{ title }}\
            <button v-on:click="$emit(\'remove\')">Remove</button>\
            </li>\
        ',
        props: ['title']
    })

    new Vue({
        el: '#todo-list-example',
        data: {
            newTodoText: '',
            todos: [
            {
                id: 1,
                title: 'Do the dishes',
            },
            {
                id: 2,
                title: 'Take out the trash',
            },
            {
                id: 3,
                title: 'Mow the lawn'
            }
            ],
            nextTodoId: 4
        },
        methods: {
            addNewTodo: function () {
            this.todos.push({
                id: this.nextTodoId++,
                title: this.newTodoText
            })
            this.newTodoText = ''
            }
        }
    })
</script>
</html>